German 39 08 553 C1, Thomas et al., describes a gas discharge lamp which includes a fill of deuterium or hydrogen within a cylindrical bulb made of quartz glass. A support structure supports an anode and a cathode. A diaphragm is located in the housing to constrict a discharge or arc between the electrodes. The cathode is located outside of, or laterally of an axis defined by the radiation path through the opening of the diaphragm. The structure supporting the anode and cathode is formed with a window, similar to a diaphragm opening, removed or cut from the material of the structure to provide for shielding of cathode emitter material. Only a single diaphragm is possible because of the arrangement of the structure; consequently, only a single plasma region can be obtained.
U.S. Pat. No. 5,327,049, Smolka et al., relates to an electrodeless discharge lamp with an apertured diaphragm body therein.